JPH1011735A - Magnetic recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a magnetic recording medium having good perpendicular magnetic orientation to enable a high density recording by forming a Zr layer on a nonmagnetic substrate and then a CoCr alloy magnetic thin film on the Zr layer. SOLUTION: After a disk type blue plate glass substrate 1 is subjected to cleaning with hot sulfuric acid at 90 deg.C for 15min and to ultrasonic cleaning for 15min, the substrate is cleaned with water and dried. The substrate 1 is mounted on a DC magnetron sputtering device having a 6-inch target and the device is evacuated. Zr is deposited to form a Zr layer 2 having 60Å thickness on the substrate 1 under conditions of 90mm distance between the substrate and the target and at 200 deg.C substrate temp. Then the substrate is cooled to room temp. and taken out. The substrate is again mounted in a 6-inch DC magnetron sputtering device and the device is evacuated. CoCr21Pt12.5 is deposited to form a CoCrPt layer 3 having 1300Åthickness on the Zr layer 2 under conditions of 90mm distance between the substrate and the target, 0.45mTorr Ar sputtering pressure and at 200 deg.C substrate temp.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium such as a magnetic disk and a magnetic tape.

[0002]

2. Description of the Related Art In recent years, in order to store a large amount of information in a medium as small as possible, no demagnetizing field is generated in principle.
Attention has been paid to perpendicular magnetic recording which can perform magnetic recording at a higher density. As a magnetic medium for the perpendicular magnetic recording, a CoCr-based alloy such as CoCr and CoCrPt is used. To increase the recording density, the gap between the head and the magnetic recording medium (head flying height) is reduced,
Since it is necessary to reduce the protective film thickness of the magnetic recording medium, an extremely smooth mirror-finished substrate is required.

[0003]

As described above, a glass substrate or the like has been conventionally used as a material of a non-magnetic substrate for performing an extremely smooth mirror finish. However, there is a problem that even when a CoCr-based alloy is formed directly on a glass substrate, the magnetic orientation in the vertical direction is not so high, and the characteristics as a recording medium are not good. Accordingly, it is an object of the present invention to provide a magnetic recording medium having excellent perpendicular magnetic orientation characteristics even when a mirror-finished non-magnetic substrate suitable for high-density recording is used.

[0004]

As means for achieving the above object, a Zr layer is provided on a non-magnetic substrate.
An object of the present invention is to provide a magnetic recording medium characterized in that a magnetic thin film made of a CoCr-based alloy is provided on a layer.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention improves the perpendicular magnetic orientation characteristics of a magnetic recording medium by forming Zr on a non-magnetic substrate such as a glass substrate and forming a CoCr-based alloy on the Zr. It is to let.

[0006]

【Example】

<Embodiment 1> First, embodiments of the magnetic recording medium of the present invention will be described with reference to the drawings. FIG. 1 is a partial sectional view showing Embodiment 1 of the magnetic recording medium of the present invention. The method of manufacturing the magnetic recording medium shown in FIG. 1 is based on the following method.
After 15 minutes of ultrasonic cleaning, the substrate is washed with water and dried. This glass substrate 1 was attached to a DC magnetron sputtering apparatus having a 6-inch target, and the ultimate vacuum degree was 3 × 10
Exhaust to ^-6 Torr. Then, at a substrate-target distance of 90 mm, an argon sputtering pressure of 2 mTorr, and a substrate temperature of 200 ° C., Zr is formed on this glass substrate 1 to a thickness of 60 A (Zr layer 2). After the film formation, the temperature of the substrate is lowered to room temperature, and is taken out. This was mounted again in a 6-inch DC magnetron sputtering apparatus, and 2 × 10 ⁻⁷
Exhaust to Torr. 90m distance between substrate and target
m, an argon sputtering pressure of 0.45 mTorr, and a substrate temperature of 200 ° C., a CoCr 21 Pt 12.5 (a
(% t%) was formed to a thickness of 1300 A (CoCrP
t layer 3).

Example 2 A disk was prepared in the same manner as in Example 1 except that the thickness of the Zr layer 2 was set to 600 A.

<Embodiment 3> After the Zr layer 2 is formed, CoCrPt is continuously taken out without being taken out of the sputtering apparatus.
A disk was prepared in the same manner as in Example 1 except that the layer 3 was formed.

Comparative Example 1 A disk was prepared in the same manner as in Example 1 except that a CoCr21Pt12.5 (CoCrPt layer 3) was formed directly on the glass substrate 1 without forming a Zr layer.

[0010] The CoCrPt layers 3 of Examples 1 to 3 and Comparative Example 1 thus produced were subjected to a vibrating sample magnetometer (VS).
M), the magnetic properties in the in-plane direction of the disk and in the direction perpendicular to the substrate surface were measured. Note that the applied magnetic field by the VSM was 10 K (Oe). Table 1 shows the measurement results.

[0011]

[Table 1]

Here, the meaning of Rs┴ / Rs‖ is as follows. When this value is large, it indicates that the magnetic orientation is strong in the direction perpendicular to the substrate surface. Therefore,
In a perpendicular film, the higher this value is, the easier it is to perform perpendicular recording.
As Rs┴ / Rs‖ approaches 1, the perpendicular magnetic orientation weakens and the in-plane magnetization becomes dominant, and when it becomes 1 or less, the film becomes an in-plane magnetization film.

Referring to Table 1, Rs┴ / Rs の of Comparative Example 1 having no Zr layer is as small as 1.21 and the perpendicular magnetic orientation is weak. It can be seen that the orientation is strengthened. Further, Examples 1 to
In No. 3, Hc in the vertical direction is also larger than that in Comparative Example 1. For these reasons, after forming a Zr layer, CoCrP
By forming the t layer, it can be said that the perpendicular magnetic orientation is enhanced.

If the Zr layer 2 is too thin, it will not be a continuous film, so the thickness is preferably 30 A or more. Conversely, 2000
If the thickness is larger than A, the particles grow and the surface becomes rough due to the irregularities, so that they are not suitable as a high-density recording medium. Therefore, the thickness of the Zr layer is desirably in the range of 30A to 2000A.

The magnetic film is not limited to CoCrPt, and the same effect can be obtained by using a CoCr-based magnetic film such as CoCr or CoCrTa. Similar effects can be obtained even when a plastic substrate or a polymer substrate such as PET (polyethylene terephthalate) is used as the substrate other than the glass substrate. In order to use these recording media prepared in the above embodiments as disc-shaped recording media, carbon or SiO ₂ is formed as a lubricating film on a CoCr-based alloy (CoCrPt layer 3) (carbon layer 4). Further, it is necessary to apply a lubricant (lubricating layer 5) thereon to form a magnetic disk.

[0016]

According to the magnetic recording medium of the present invention, by providing a Zr layer between a non-magnetic substrate and a CoCr-based alloy, perpendicular magnetic alignment can be achieved even when a mirror-like non-magnetic substrate such as a glass substrate is used. Good magnetic recording medium,
There is an effect that high-density recording becomes possible.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing the structure of a magnetic recording medium according to Examples 1 to 3 of the present invention.

FIG. 2 is a partial cross-sectional view illustrating a magnetic recording medium of Comparative Example 1.

[Explanation of symbols]

 Reference Signs List 1 non-magnetic substrate 2 Zr layer 3 CoCr-based alloy (CoCrPt layer) 4 carbon layer 5 lubrication layer

Claims (4)

[Claims] A magnetic recording medium comprising: a Zr layer provided on a non-magnetic substrate; and a magnetic thin film made of a CoCr-based alloy provided on the Zr layer. 2. The magnetic recording medium according to claim 1, wherein CoCrPt is used as said CoCr-based alloy. 3. The magnetic recording medium according to claim 1, wherein the axis of easy magnetization of the magnetic thin film is perpendicular to the substrate surface of the non-magnetic substrate. 4. The magnetic recording medium according to claim 1, wherein said Zr layer has a thickness of 30A.
(Angstrom) or more and 2,000 A or less.